The present invention relates to a display driver, a display device, and a drive method.
A precharge technology which increases the liquid crystal drive speed of an active matrix type liquid crystal display device (display device in a broad sense) is known. In this precharge technology, a data line is precharged to a predetermined potential before driving the data line based on display data to reduce the amount of charging/discharging of the data line accompanying supply of a drive voltage based on the display data.
This precharge technology is disclosed in Japanese Patent Application Laid-open No. 10-11032 and Japanese Patent Application Laid-open No. 2002-229525, for example. In Japanese Patent Application Laid-open No. 10-11032, different direct-current potentials are provided in advance, and a switch is provided between the direct-current potentials and the data line. This precharge technology controls connection between the direct-current potentials provided in advance and the data line by controlling the switch corresponding to the polarity of liquid crystal reversal drive. According to this precharge technology, the amount of charging/discharging of the data line accompanying drive is small even if the precharge cycle is reduced, whereby an increase in power consumption can be prevented and an accurate voltage can be supplied to the data line.
Japanese Patent Application Laid-open No. 2002-229525 discloses a technology of controlling supply of a precharge voltage corresponding to the result of a comparison between display data for the preceding and current horizontal scanning periods. This enables precharging to be omitted depending on the drive voltage in the horizontal scanning period before precharging. Therefore, precharging is not necessarily performed irrespective of the drive voltage in the horizontal scanning period before precharging, whereby power consumption accompanying a change in potential of the data line can be reduced.